Apparatus and methods for producing shrink-wrap packaging

Abstract

A vacuum table ( 18 ) includes an introduction section ( 102 ) in fluid communication with a vacuum chamber ( 120 ) and a compartment ( 139 ) dividable by an adjustment partition ( 156 ) into primary and secondary vacuum chambers ( 139 a, 139 b ). Adjustment plates ( 130 ) having adjustment apertures ( 138 ) are positionable over apertures ( 128 ) of the conveying surface ( 100 ) of the vacuum table ( 18 ) generally perpendicular to the conveying direction. Film ( 20 ) extends from between the nip of pinch rollers ( 12, 13 ) to the conveying surface ( 100 ) and is tensioned therebetween to be cut in excess of 105 cuts per minute by a servo motor controlled rotary cutter ( 30 ) which stops after each cut. The shaft ( 32 ) of the rotary cutter ( 30 ) includes a bore ( 310 ) extending from the idle end to provide servo-control loop stability.

The invention claimed is: 
     
       1. A vacuum table comprising, in combination:
 a vacuum chamber having a top conveying surface including a plurality of air apertures formed therein; 
 a carrier moving over the top conveying surface in a conveying direction, with the carrier including an upper surface for abutment with an element to be conveyed and a lower surface for abutment with the top conveying surface, with the carrier providing air communication between the element and the vacuum chamber through the plurality of air apertures with the carrier comprising a plurality of belts moving in the conveying direction; and 
 an adjustment plate adjustably positioned in an adjustment direction perpendicular to the conveying direction, with the adjustment plate blocking some of the plurality of air apertures of the top conveying surface, with the belts having a spacing in the adjustment direction, with the plurality of air apertures aligned with the spacings of the plurality of belts, with the plurality of belts providing air communication between the upper surface and the element. 
 
     
     
       2. The vacuum table of  claim 1  with the plurality of belts being of a saw tooth style in the conveying direction. 
     
     
       3. The vacuum table of  claim 2  further comprising, in combination: sidewalls located in the spacings between adjacent belts of the plurality of belts, with the sidewalls having a height generally equal to a distance between the upper and lower surfaces of the carrier, with each air aperture having an extent in the adjustment direction greater than the sidewall. 
     
     
       4. The vacuum table of  claim 3  with the sidewalls extending over the air apertures, with the sidewalls including first and second recesses extending from opposite sides of each sidewall in the adjustment direction, with one of the air apertures aligned with the first and second recesses. 
     
     
       5. The vacuum table of  claim 4  with the adjustment plate including adjustment apertures, with adjustment of the adjustment plate in the adjustment direction causing the adjustment apertures to be aligned or misaligned with the air apertures of the top conveying surface. 
     
     
       6. The vacuum table of  claim 5  with the adjustment apertures having a length parallel to the adjustment direction, with the plurality of adjustment apertures arranged in a series of increasing lengths in the adjustment direction. 
     
     
       7. The vacuum table of  claim 1  with the adjustment plate having a thickness, with the vacuum chamber including first and second cross members extending in the adjustment direction, with each of the first and second cross members having a depression of a depth generally equal to the thickness of adjustment plate, with the depression including a protrusion, with the adjustment plate including first and second parallel slots extending parallel to the adjustment direction, with the slots receiving and being elongated relative to the protrusions of the first and second cross members. 
     
     
       8. The vacuum table of  claim 7  further comprising, in combination: a shaft rotatable about an axis parallel to the adjustment direction; and a block in gearing relation to the shaft and fixed to the adjustment plate. 
     
     
       9. The vacuum table of  claim 1  further comprising, in combination: another adjustment plate adjustably positioned in the adjustment direction, with the adjustment plates being spaced from each other in the adjustment direction. 
     
     
       10. The vacuum table of  claim 9  with the top conveying surface being intermediate the carrier and the adjustment plate. 
     
     
       11. Vacuum table comprising, in combination:
 a vacuum chamber having a top conveying surface including a plurality of air apertures formed therein; 
 a carrier moving over the top conveying surface in a conveying direction, with the carrier including an upper surface for abutment with an element to be conveyed and a lower surface for abutment with the top conveying surface, with the carrier providing air communication between the element and the vacuum chamber through the plurality of air apertures; 
 an adjustment plate slideable beneath and parallel to the top conveying surface to be adjustably positioned in an adjustment direction perpendicular to the conveying direction, with the adjustment plate including adjustment apertures, with adjustment of the adjustment plate in the adjustment direction causing the adjustment apertures to be aligned or misaligned with the air apertures of the top conveying surface and blocking some of the plurality of air apertures of the top conveying surface; 
 a shaft rotatable about an axis parallel to the adjustment direction; and 
 a block in gearing relation to the shaft and fixed to the adjustment plate. 
 
     
     
       12. The vacuum table of  claim 11  further comprising, in combination: another adjustment plate adjustably positioned in the adjustment direction, with the adjustment plates being spaced from each other in the adjustment direction. 
     
     
       13. The vacuum table of  claim 12  with the top conveying surface being intermediate the carrier and the adjustment plate. 
     
     
       14. The vacuum table of  claim 1  with the adjustment apertures having a length parallel to the adjustment direction, with the plurality of adjustment apertures arranged in a series of increasing lengths in the adjustment direction. 
     
     
       15. Vacuum table including a first vacuum chamber having a conveying surface including a plurality of air apertures formed therein, a second vacuum chamber having a conveying surface including a plurality of air apertures formed therein, with an amount of vacuum being operationally different in the first and second vacuum chambers, and a carrier moving over the conveying surface of the first vacuum chamber in a conveying direction, with the carrier including an upper surface for abutment with an element to be conveyed and a lower surface for abutment with the conveying surface of the first vacuum chamber, with the carrier providing air communication between the element and the first vacuum chamber through the plurality of air apertures, wherein the carrier moves from the first vacuum chamber in the conveying direction over the conveying surface of the second vacuum chamber, with the carrier providing air communication between the element and the second vacuum chamber through the plurality of air apertures. 
     
     
       16. The vacuum table of  claim 15  further comprising, in combination: a compartment; and an adjustment partition in the compartment dividing the compartment into the first and second vacuum chambers, with the adjustment partition adjustable in the conveying direction to vary extents of the first and second vacuum chambers parallel to the conveying direction. 
     
     
       17. The vacuum table of  claim 16  wherein the amount of vacuum in the first vacuum chamber is constant and in the second vacuum chamber is variable. 
     
     
       18. The vacuum table of  claim 17  further comprising, in combination: a shaft rotatable about an axis parallel to the conveying direction, with the adjustment partition in gearing relation to the shaft. 
     
     
       19. The vacuum table of  claim 18  with the compartment further including a plurality of cross members extending perpendicular to the conveying direction, with the adjustment partition being adjustable to abut with one of the plurality of cross members to divide the compartment into the first and second vacuum chambers. 
     
     
       20. The vacuum table of  claim 19  further comprising, in combination: an adjustment plate adjustably positioned in an adjustment direction perpendicular to the conveying direction, with the adjustment plate blocking some of the plurality of air apertures of the conveying surfaces of the first and second vacuum chambers, with the conveying surfaces being intermediate the carrier and the adjustment plate, with the adjustable plate being slideable relative to the plurality of cross members. 
     
     
       21. The vacuum table of  claim 19  further comprising, in combination: an introduction vacuum chamber with the first vacuum chamber located intermediate the introduction vacuum chamber and the second vacuum chamber, with the amount of vacuum being operationally different in the introduction, first and second vacuum chambers, with the introduction vacuum chamber including a conveying surface, with the carrier moving over the conveying surface of the introduction vacuum chamber, with the amount of vacuum in the introduction chamber being variable and having a maximum amount of vacuum greater than the amount of vacuum in the first vacuum chamber. 
     
     
       22. The vacuum table of  claim 21  wherein the conveying surface of the introduction vacuum chamber comprises a first surface and a second surface arranged at an obtuse angle, with the second surface extending linearly with the conveying surface of the first vacuum chamber. 
     
     
       23. The vacuum table of  claim 22  with the carrier comprising a plurality of belts moving in the conveying direction, with the belts having a spacing in the adjustment direction, with the plurality of air apertures aligned with the spacings of the plurality of belts, with the plurality of belts providing air communication between the upper surface and the element. 
     
     
       24. The vacuum table of  claim 23  wherein the introduction section further comprises, in combination: sidewalls located in the spacings between adjacent belts of the plurality of belts, with the sidewalls having a height generally equal to a distance between the upper and lower surfaces of the carrier, with each air aperture having an extent in the adjustment direction greater than the sidewall. 
     
     
       25. The vacuum table of  claim 15  wherein the amount of vacuum in the second vacuum chamber is constant and in the first vacuum chamber is variable. 
     
     
       26. The vacuum table of  claim 25  wherein the amount of vacuum in the first vacuum chamber has a maximum amount of vacuum greater than the amount of vacuum in the second vacuum chamber. 
     
     
       27. The vacuum table of  claim 26  wherein the conveying surface of the first vacuum chamber comprises a first surface and a second surface arranged at an obtuse angle, with the second surface extending linearly with the conveying surface of the second vacuum chamber. 
     
     
       28. The vacuum table of  claim 27  with the carrier comprising a plurality of belts moving in the conveying direction, with the belts having a spacing in the adjustment direction, with the plurality of air apertures aligned with the spacings of the plurality of belts, with the plurality of belts providing air communication between the upper surface and the element. 
     
     
       29. The vacuum table of  claim 28  wherein the first vacuum chamber further comprises, in combination: sidewalls located in the spacings between adjacent belts of the plurality of belts, with the sidewalls having a height generally equal to a distance between the upper and lower surfaces of the carrier, with each air aperture having an extent in the adjustment direction greater than the sidewall. 
     
     
       30. The vacuum table of  claim 29  further comprising, in combination: a pair of pinch rollers, with a plane tangent to an abutment of the pair of pinch rollers lying generally in a same plane as the conveying surface of the second vacuum chamber; and a rotary cutter positioned between the pair of pinch rollers and the second vacuum chamber, with the amount of vacuum of the first vacuum chamber being at the maximum amount of vacuum when the rotary cutter is rotated. 
     
     
       31. Vacuum table comprising, in combination:
 a vacuum chamber having a top conveying surface including a plurality of air apertures formed therein; 
 a carrier moving over the top conveying surface in a conveying direction, with the carrier including an upper surface for abutment with an element to be conveyed and a lower surface for abutment with the top conveying surface, with the carrier providing air communication between the element and the vacuum chamber through the plurality of air apertures; and 
 an adjustment plate slideable beneath and parallel to the top conveying surface to be adjustably positioned in an adjustment direction perpendicular to the conveying direction, with the adjustment plate including adjustment apertures, with adjustment of the adjustment plate in the adjustment direction causing the adjustment apertures to be aligned or misaligned with the air apertures of the top conveying surface and blocking some of the plurality of air apertures of the top conveying surface, with the adjustment plate having a thickness, with the vacuum chamber including first and second cross members extending in the adjustment direction, with each of the first and second cross members having a depression of a depth generally equal to the thickness of adjustment plate, with the depression including a protrusion, with the adjustment plate including first and second parallel slots extending parallel to the adjustment direction, with the slots receiving and being elongated relative to the protrusions of the first and second cross members. 
 
     
     
       32. The vacuum table of  claim 31  further comprising, in combination: a shaft rotatable about an axis parallel to the adjustment direction; and a block in gearing relation to the shaft and fixed to the adjustment plate.